I recently got myself a copy of 64 bit windows 7 and all of my games on steam like HL2 and Bad Company 2 all run in 32 .I have read that hl2 will automatically detect if its on a 64 bit os. When I go into the task manager it shows that the app is *32 instead of what it should be. Any suggestions?

Games typically don't "Run" in 64-bit modes. What they say is that the game can detect if you are running a 64-Bit OS and looks for the appropriate resources, drivers, runtimes, etc. You can run 32-bit applications such as games in 32-bit mode with no ill effects on a 64-bit OS.

You would essentially need to choose to install a "64-bit only game" or "include a 64-bit option" for it to run in 64-bit mode, and to my knowledge there aren't any games that have a 64-bit version. There isn't anything the average user would benefit from 64-bit games currently anyways, and since you're asking about 64-bit games, you aren't a high-end user that might be able to tweak things to get a boost in 64-bit gaming.